A power grid may be operated at a sea ground or subsea. A power grid may include an adjustable speed drive (ASD) with one or more power cells that may have a DC-link capacitor as a component. Each power cell may contain a large DC-link capacitor. In a subsea application, smaller capacitors may be used for power supply and circuit boards. In a subsea application or subsea power grid, components (including the power cell in the subsea ASD) may be located in a pressure-compensated oil volume (e.g., contained within a vessel or enclosure). The phrase “pressure-compensated” signifies that the pressure inside the vessel is balanced to the ambient pressure. The ambient pressure (e.g., outside the vessel or enclosure) may be very high (e.g., 50 bar to 400 bar) but the differential pressure (e.g., between the inside and outside of the vessel or enclosure) may be relatively low (e.g., 0.1 bar to 2.0 bar, or about 1 bar). Thus, the components of the ASD or other components of the subsea application may be exposed to the same ambient pressure as the water pressure surrounding the subsea power grid. A subsea application may take place at a depth of about 3000 m below sea level. At this depth, a pressure of about 300 bar prevails. Therefore, components to be used in subsea applications may have to withstand and operate properly at this pressure.
Self-healing film capacitors have a low dissipation factor and are used, for example, on circuit boards. Self-healing film capacitors are suitable for high current pulses. Such high current pulses may occur, for example, when capacitors are used in snubber circuits for semiconductor applications.
Film capacitors may include faults that hamper the operation thereof. Therefore, in accordance with a standard manufacturing process for a self-healing film capacitor, a self-healing act may be performed. The manufacturing stages may be roughly categorized as: metalizing, film slitting, winding, flattening (e.g., for flat windings) or cutting (e.g., for stacked windings), and contact layer application (e.g., “shoopage”). After the above-described process stages, the manufactured capacitors may have produced defects in the dielectric film or metallization (e.g., defects, weaknesses, pinholes and flaws). In addition, foreign or undesired particles may be trapped between film layers, or there may be production inaccuracies in the dielectric film or metallization layer. Conventionally, a healing process is performed in order to clear manufacturing faults.
Conventional healing processes for healing a capacitor (e.g., a self-healing film capacitor) may not be of sufficient accuracy or reliability for all conditions, such as for preparing capacitors for subsea applications.